Force gauge



` Fleta.v A,f6

HiringT9218,` R. 1;.l Mmmm "2A-45307 FORCE v @man v Fiied Haren' 51, 1943 l Y 'im @il 20 A, 20 I8 /4a 2l Patented July 13, 1948 i 222,445,3cr n A Y l Forum GAUGE; ``:armeniall). Minaiin, Newmark, for., assigner tojthe United States Tof Amerieaasxrepresentefd I by the Secretaryofthe Navy e 't Y fappiicatiqn Marc/11.31, rscfaifsefialnaAsll-S "'rhis .invention relates .to testing f devis 'and hasparticular reference tov a novel gaugel for in- /dcatin'gthe' magnitudes of the forces to' which ".aflr't'ary projectile is subjected, such-as setback {andiinpactj The new gauge 'is simple and com- -i pact in construction, is adapted formanufacture at low cost and operates positivelyr and reliably .to provide accurate indications.k n y v-One object of the invention resides in the provision `of a novel force-gauge which may be 1 :mounted in a rotary .projectile'for use in comparing -the force ofsetback-during acceleration of the-projectile in the gun barrel with the force Iof impact when the projectile strikes anobject,

such yasthc ground, so that informationv concerningthe conduct of elements mounted in the projectile may be obtained lA gaugemade-inac -cordance with-l the invention comprises va marker Aoperable.'by-.a-force of setback, and arecording mediumfor --receiving from thewmarker an `indica-tion ofthe magnitude .ofthe force Vof setback. W-henthe recording medium has receivedfrom the marker` any indication of the initialhsetback lforefrthe Amarker :and the recording medium are moved relatively,- as bycentrifugal ,action due-to rotation 1of'thei1projecti1e, whereby the recording medium is in position to receive from the marker an additional iridicationof the final setback force when the projectile strikes Aan object. In the preferred construction; the'reco'r'ding' mefa-Y setback gauge Y of simple construction ,fwhich occupies only a small space in the projectile.

These and other -objects of the invention may be better understood by reference to the accompanying drawing, in which Fig. 1 is a side View of a projectile embodying one form of the new gauge, with part of the projectile broken away to show the gauge;

Fig. 2 is an enlarged longitudinal sectional view of the gauge illustrated in Fig. 1, showing the recording means in its initial position;

Fig. 3 is a sectional view on the line 3--3 in Fig. 2;

Fig. 4 is a view similar to Fig. 2 showing the recording means in its final position;

Fig. 5 is a sectional view on the line 5-5 in Fig. 4;

lFig. 6 -isanerilarge'd 'view of part 'ofthe `gauge ,illustrated in Fig. 2, showing the position of'ithe parts when 'the projectile strikes an obj ect;

lFig. A'Tis af-perspective-.view ofgpartiof therhousingof thegaugaiand v`Fig. "8 is aperspectiveview 'of the recorder.

` Referring :to "the drawing,the setback gauge I0 'is 'shown' in y a projectile comprising a casing vII andainose I2 secured'to the casing., as'by means king forwardlyflomthe ibottomof the re'cessis a fpinl' c disposed on `'the' axis of the housing, which 'jco'rrespondsto thejaxisofthe projectile. A recjord "receiving body "I 9V is: mounted 'in 'the ,recess '.I4'a"'onthe axis` pin I8 and, as ishown, .comprises -two' slugs 2B' and 2 I of' relativelypsoft metal, such 'as lead, 'joined 'together .by va relatively vthin frang'ble web `22 having a central opening through which the pin I8 projects. The recess Mais considerably longer thanithe impression ',receivingbodyillso that'there is a substantial clearance betweenthe outer.r` ends ofthe slugszll, 2l"and"theadjacentfends f: the recess.

In the rear'gface of the front housingsection' I5 "are'jtwo spaced sockets24 .and,25 zadjacent the outer" end porti'ons Lof 'the slugs 2i! and? 2 I, respectively. The sockets l2 4 ;an'd A25 contain markers 24a and"25a',respectivelminthe form of steel ballsysuchas hardenedball bearings. vThe markers fit loosely in the sockets so that they arev mov- Vable rcarwardlyagainstv the slugs20and `2I under a-force of setback.

"When 'the projectile. is "red v'from a gun, the initia'ljfcrce Tof* setback.incident to'y acceleration 'of theprojectile inthe'gun barrel causes 'the markers 24a and 25a to move rearwardly with considerable force against the recorder I9, which is held stationary by the bottom of recess Ma, and, as a result, the markers make depressions 21 in the outer portions of the relatively soft slugs Z and 2l, respectively. Thereafter, when the projectile approaches its maximum velocity and maximum speed of rotation, the centrifugal force on the slugs 20 and 2| is sufficient to fracture the web 22. Accordingly, the slugs move outwardly in the recess I la under the action of the centrifugal force, the outward movement of the slugs being limited by the ends of the recess. It will be understood that by the time the centrifugal force on amasar' 3 the slugs is s'uicient to break the web 22', the pressure of the markers on the slugs is relieved due to dissipation of the initial force of setback, so that the markers do not afford any appreciable resistance to breaking of the web or to outward movement of the slugs in the recess 14a. Since the markers 24a and 25a are spherical, tl'ielr roll easily out of the depressions 21 on outward movement of the slugs and roll against the side walls of sockets 24 and 25, -respectively, under the centrifugal force. In ring the projectile for test purposes, its flight is such that the projectile strikes the ground base first in a substantial- 1y vertical descent, Accordingly, when the projectile strikes the ground, the markers Maand 25a are again moved rearwardly against the slugs and 2l, respectively, under the nal force of setback. However, since the slugs are now in their outermost positions in recess I 4a, the inner por-v tions of the slugs receive the resulting impressions 28 from the markers, as shown in Figs. 4 and 6.

It will be apparent that the diametersv or depths of the depressions 2'| and 28'are measures of the initial and final forces of setback, respectively, in the projectile. By comparing the relative sizes of the depressions 21 and 28, itis possiblev to compare the forces of setback incident to ring the projectile with the forces of impact when the projectile strikes the ground. The gauge is particularly suited for testing various components Vto be used in projectiles. For example, bythe usen of the new gauge it may be determinedy whether forces greater than a component canreasonably be expected to withstand are present in the pro-v jectile when it is fired from thegun or when it strikes an ob-ject such as the ground.

It will be understood that many changes may be made in the arrangement and details of parts described without departing from the spirit of the invention as set forth in the accompanying claims. I, therefore, do not wish to be' limited to the exact details shown anddescribed as thel preferred form only has been shownr by wa'yof illustration.

I claim:

l. A setback gauge for rotary projectiles which comprises a pair of markers operable by a force of setback, a pair of slugs for receiving from said markers an indication of the magnitude of the force of setback, and means for holding the slugs in predetermined positions relative to the markers and operable by centrifugal force to release the slugs, the slugs when released being movable by centrifugal force to different positions vrelative to the markers.

2. A setback gauge for rotary projectiles which comprises a housing having a recess and a communicating socket therein, a recording medium in a predetermined position in the recess and movable to a second position under the influence of centrifugal force, and a marker formed of mated rial relatively harder than that of the recording medium freely contained in the socket and free to bear against the recording medium whereby the initial and nal setback forces will cause the marker to produce two separate impressions on the recording medium, the sizes of which indicate the magnitude of the corresponding forces.

3. A gauge adapted for mounting in a, projectile subjected to centrifugal force when in flight comprising a housing having a recess and at least two sockets therein, a recording medium in a predetermined position in the recess and movable to a second position under the influence of centrifugal force, a marker formed of material relatively harder than that of the recording medium freely contained in each of the sockets and free to bear against the recording medium, at least one marker being so positioned relative to the recording medium whereby the initial setback force will cause the marker to produce an impression on the recording medium, and at least one marker being so positioned relative to the recording medium whereby the force of nal impact of the projectile will cause the marker to produce another separate impression on the recording medium, the sizes of the impressions indicating the magnitude of the corresponding forces.

4. A gauge adapted for mounting in a projectile subjected to centrifugal force when in flight comprising a housing having a recess and at least two sockets therein, recording means in said recess comprising a pair of slugs retained in a predetermined position relative to each other and relative to said sockets, said slugs beingV separable under the action of centrifugal force whereby the slugs move outwardly within the recess to diierent posi tions relative to the said sockets, a marker formed of material relatively harder than that of the slugs freely contained in each of theY sockets and each free to bear against one of the slugs whereby the initial setback force and the force of nal impact of the projectile will'cause the markers to produce separate impressions on at least one slug, the size of the impressions indicating the magnitnde of the corresponding forces.

` RAYMOND D. MINDLIN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,155,635 Bennett. Apr. 25, 1939 2,195,451 Edwards Apr. 2, 194

FOREIGN PATENTS Number Country Date 7,161 Switzerland Aug. 4, 1883 

